NOAO >   Observing Info >   Approved Programs >   2003B-0368

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Proposal Information for 2003B-0368


PI: Lucas Macri, NOAO, lmacri@noao.edu
Address: NTSS, 950 N Cherry Avenue, Tucson, AZ 85719, USA

CoI: Dimitar Sasselov, Harvard-Smithsonian CfA
CoI: Krzysztof Stanek, Harvard-Smithsonian CfA

Title: Improving the Cepheid Distance Scale (II)

Abstract: We propose to improve the Cepheid Distance Scale through a study of one of its leading systematic uncertainties: the metallicity dependence of the Cepheid Period-Luminosity relation. We have recently completed a survey for variable stars in M33 covering over 1000 \sq \arcmin. We have discovered approximately 700 Cepheids that span a range in metal abundance of 1 dex, making them ideally suited for a characterization of the metallicity effect. We propose to obtain a multi-wavelength dataset of unprecedented photometric quality, with modest phase coverage, to study this effect. Given our knowledge of the positions and periods of the variables, only a small amount of telescope time is required to obtain high-quality light curves. This study will result in an accurate and precise characterization of the metallicity dependence of the Cepheid Period- Luminosity relation across the optical and near-infrared, sensitive to any values of importance for the Extragalactic Distance Scale.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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